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Durable Objects – Outbound connections keep Durable Objects alive

2 minutesPosted inCloudflare

Durable Objects now remain alive for the duration of active outbound connections created via connect() or an outbound WebSocket. Previously, a Durable Object would be evicted after 70-140 seconds of no incoming traffic, even if the object had an open outbound connection, which is a common pattern when streaming responses from a large language model (LLM) over TCP or an outbound WebSocket.

With this change, each active outbound connection prevents eviction. Once all outbound connections close, the standard 70-140 second inactivity window applies before the Durable Object is evicted.

Before: streaming connections were cut off by eviction

Timeline showing a Durable Object evicted 70-140 seconds after the last incoming request, cutting off an in-flight LLM stream while the outbound connection is still open

After: active outbound connections keep the Durable Object alive

Timeline showing the same outbound stream completing because the active connection keeps the Durable Object alive, with the inactivity window starting only after the connection closes

If you are building agents on Cloudflare, this is especially relevant. An agent that streams tokens from an LLM while calling models, or that performs long-running tasks over an outbound connection, now stays alive for the duration of that connection instead of being evicted mid-stream.

Limits:

  • Each outbound connection keeps the Durable Object alive for a maximum of 15 minutes. After 15 minutes, the connection stops preventing eviction (the connection itself continues operating), and the standard eviction rules resume.
  • The Durable Object’s existing per-account instance limits still apply.

For more information, refer to Lifecycle of a Durable Object.

Source: Cloudflare



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